Cardiac pacing leads having tines that engage heart tissue and urge electrodes into contact with the endocardium in a direction parallel to the lead axis are disclosed by G. A. Bornzin in U.S. Pat. No. 4,502,492 and J. E. Sluetz et al in U.S. Pat. No. 4,662,382. Fibrotic growth of heart tissue around the electrode and tines prevent removal of the electrode from the heart without substantial damage to the heart. A corkscrew connected to an electrode is disclosed by R. G. Baker in U.S. Pat. Nos. 4,679,572 and 4,762,136 to provide active fixation of the electrode to the myocardium. The electrode must be rotated to attach and remove the electrode from the heart tissue. Structures used to rotate the electrodes having corkscrew attachment devices as shown by S. L. Miller in U.S. Pat. No. 4,628,943 and W. A. McArthur in U.S. Pat. No. 4,649,938. Fibrotic growth of heart tissue around electrode and corkscrew. Forced rotation of the electrode and corkscrew can cause heart tissue damage. Another structure for implanting an electrode to heart tissue is disclosed by G. Schmitt in U.S. Pat. No. 3,754,555 and D. E. Karr et al. This structure has a pair of resilient prongs or wire springs projected from the distal end of the electrode into the heart tissue. The springs are enclosed within a sleeve to permit insertion of the electrode into the heart. When the electrode is positioned in contact with the endocardium, a stylet is used to move the springs forwardly out of the sleeve into the heart tissue. The stylet is also used to pull the springs back into the sleeve to retract the springs from the heart tissue.